<?php
/**
 * Aoedia abilities for scheduling posts and pages.
 *
 * Scheduling is the only way Aoedia can lead to publication, so it needs the
 * right to publish, a date in the future, and the user's approval of that
 * exact date.
 *
 * @package Aoedia
 */

defined( 'ABSPATH' ) || exit;

/** Abilities that schedule or unschedule a post or page. */
const AOEDIA_SCHEDULE_ABILITIES = array( 'aoedia/schedule-post', 'aoedia/unschedule-post' );

/** The earliest a post can be scheduled, in seconds from now. */
const AOEDIA_SCHEDULE_MIN_DELAY = 5 * MINUTE_IN_SECONDS;

/** The latest a post can be scheduled, in seconds from now. */
const AOEDIA_SCHEDULE_MAX_DELAY = 2 * YEAR_IN_SECONDS;

/**
 * Registers the Aoedia scheduling abilities.
 */
function aoedia_register_schedule_abilities(): void {
	$id_property = array(
		'type'        => 'integer',
		'description' => __( 'The post or page ID.', 'aoedia' ),
	);

	$output_schema = array(
		'type'       => 'object',
		'properties' => array(
			'id'       => array( 'type' => 'integer' ),
			'status'   => array( 'type' => 'string' ),
			'date'     => array( 'type' => 'string' ),
			'edit_url' => array( 'type' => 'string' ),
		),
	);

	wp_register_ability(
		'aoedia/schedule-post',
		array(
			'label'               => __( 'Schedule Post', 'aoedia' ),
			'description'         => __( 'Schedules a draft or pending post or page to be published automatically at a future date, or changes the date of one already scheduled. The date is in the site\'s time zone, at least 5 minutes and at most 2 years ahead. Propose this only when the user asks for scheduling.', 'aoedia' ),
			'category'            => 'aoedia-content',
			'input_schema'        => array(
				'type'                 => 'object',
				'properties'           => array(
					'id'   => $id_property,
					'date' => array(
						'type'        => 'string',
						'pattern'     => '^\d{4}-\d{2}-\d{2}[ T]\d{2}:\d{2}(:\d{2})?$',
						'description' => __( 'When to publish, as YYYY-MM-DD HH:MM in the site\'s time zone.', 'aoedia' ),
					),
				),
				'required'             => array( 'id', 'date' ),
				'additionalProperties' => false,
			),
			'output_schema'       => $output_schema,
			'execute_callback'    => 'aoedia_ability_schedule_post',
			'permission_callback' => 'aoedia_can_publish_input',
			'meta'                => array(
				'annotations'  => array(
					'readonly'    => false,
					'destructive' => false,
					'idempotent'  => true,
				),
				'show_in_rest' => true,
			),
		)
	);

	wp_register_ability(
		'aoedia/unschedule-post',
		array(
			'label'               => __( 'Unschedule Post', 'aoedia' ),
			'description'         => __( 'Turns a scheduled post or page back into a draft, so it is not published.', 'aoedia' ),
			'category'            => 'aoedia-content',
			'input_schema'        => array(
				'type'                 => 'object',
				'properties'           => array( 'id' => $id_property ),
				'required'             => array( 'id' ),
				'additionalProperties' => false,
			),
			'output_schema'       => $output_schema,
			'execute_callback'    => 'aoedia_ability_unschedule_post',
			'permission_callback' => 'aoedia_can_publish_input',
			'meta'                => array(
				'annotations'  => array(
					'readonly'    => false,
					'destructive' => false,
					'idempotent'  => true,
				),
				'show_in_rest' => true,
			),
		)
	);
}

/**
 * Returns whether the current user can edit and publish the post or page in the input.
 *
 * @param mixed $input The ability input.
 * @return bool Whether they can.
 */
function aoedia_can_publish_input( $input = array() ): bool {
	$post = get_post( is_array( $input ) && isset( $input['id'] ) ? (int) $input['id'] : 0 );
	if ( ! $post || ! in_array( $post->post_type, array( 'post', 'page' ), true ) ) {
		return false;
	}

	return current_user_can( 'edit_post', $post->ID ) && current_user_can( get_post_type_object( $post->post_type )->cap->publish_posts );
}

/**
 * Parses a schedule date in the site's time zone.
 *
 * @param string $date The date, as YYYY-MM-DD HH:MM[:SS].
 * @return DateTimeImmutable|null The date, or null if it is not valid.
 */
function aoedia_parse_schedule_date( string $date ): ?DateTimeImmutable {
	$date = str_replace( 'T', ' ', $date );
	$date = 16 === strlen( $date ) ? $date . ':00' : $date;

	$parsed = DateTimeImmutable::createFromFormat( '!Y-m-d H:i:s', $date, wp_timezone() );
	// createFromFormat() rolls invalid dates such as 2026-02-31 over; refuse them instead.
	return $parsed && $parsed->format( 'Y-m-d H:i:s' ) === $date ? $parsed : null;
}

/**
 * Checks a scheduling change before it is proposed and again before it runs.
 *
 * @param string               $ability The ability name.
 * @param array<string, mixed> $input   The validated input.
 * @return true|WP_Error True, or the problem.
 */
function aoedia_validate_schedule_change( string $ability, array $input ) {
	$post = get_post( (int) $input['id'] );
	if ( ! $post ) {
		return new WP_Error( 'aoedia_post_not_found', __( 'Post not found.', 'aoedia' ) );
	}

	if ( 'aoedia/unschedule-post' === $ability ) {
		return 'future' === $post->post_status
			? true
			: new WP_Error( 'aoedia_not_scheduled', __( 'This is not scheduled.', 'aoedia' ) );
	}

	if ( ! in_array( $post->post_status, array( 'draft', 'pending', 'future' ), true ) ) {
		return new WP_Error( 'aoedia_cannot_schedule', __( 'Only drafts, posts pending review and scheduled posts can be scheduled. This one is already published or private.', 'aoedia' ) );
	}
	if ( '' === trim( $post->post_title ) ) {
		return new WP_Error( 'aoedia_cannot_schedule', __( 'Give it a title before scheduling it.', 'aoedia' ) );
	}

	$date = aoedia_parse_schedule_date( (string) $input['date'] );
	if ( ! $date ) {
		return new WP_Error( 'aoedia_invalid_date', __( 'The date is not valid. Use YYYY-MM-DD HH:MM.', 'aoedia' ) );
	}
	$delay = $date->getTimestamp() - time();
	if ( $delay < AOEDIA_SCHEDULE_MIN_DELAY ) {
		return new WP_Error( 'aoedia_invalid_date', __( 'The date must be at least 5 minutes in the future.', 'aoedia' ) );
	}
	if ( $delay > AOEDIA_SCHEDULE_MAX_DELAY ) {
		return new WP_Error( 'aoedia_invalid_date', __( 'The date must be within the next 2 years.', 'aoedia' ) );
	}

	return true;
}

/**
 * Returns the schedule date as people read it, for approval cards.
 *
 * @param string $date The date from the ability input.
 * @return string The formatted date, or an empty string if it is not valid.
 */
function aoedia_schedule_date_label( string $date ): string {
	$parsed = aoedia_parse_schedule_date( $date );
	return $parsed ? wp_date( get_option( 'date_format' ) . ' ' . get_option( 'time_format' ), $parsed->getTimestamp() ) : '';
}

/**
 * Formats the result of a scheduling change.
 *
 * @param int $post_id The post ID.
 * @return array<string, mixed> The result.
 */
function aoedia_schedule_result( int $post_id ): array {
	$post = get_post( $post_id );

	return array(
		'id'       => $post_id,
		'status'   => $post->post_status,
		'date'     => $post->post_date,
		'edit_url' => (string) get_edit_post_link( $post_id, 'raw' ),
	);
}

/**
 * Executes aoedia/schedule-post.
 *
 * @param array<string, mixed> $input The ability input.
 * @return array<string, mixed>|WP_Error The scheduled post, or an error.
 */
function aoedia_ability_schedule_post( $input = array() ) {
	$check = aoedia_validate_schedule_change( 'aoedia/schedule-post', $input );
	if ( is_wp_error( $check ) ) {
		return $check;
	}

	$date   = aoedia_parse_schedule_date( (string) $input['date'] );
	$result = wp_update_post(
		array(
			'ID'            => (int) $input['id'],
			'post_status'   => 'future',
			'post_date'     => $date->format( 'Y-m-d H:i:s' ),
			'post_date_gmt' => $date->setTimezone( new DateTimeZone( 'UTC' ) )->format( 'Y-m-d H:i:s' ),
			// Drafts keep a floating date unless told otherwise.
			'edit_date'     => true,
		),
		true
	);
	if ( is_wp_error( $result ) ) {
		return $result;
	}

	return aoedia_schedule_result( (int) $input['id'] );
}

/**
 * Executes aoedia/unschedule-post.
 *
 * @param array<string, mixed> $input The ability input.
 * @return array<string, mixed>|WP_Error The post, now a draft, or an error.
 */
function aoedia_ability_unschedule_post( $input = array() ) {
	$check = aoedia_validate_schedule_change( 'aoedia/unschedule-post', $input );
	if ( is_wp_error( $check ) ) {
		return $check;
	}

	$result = wp_update_post(
		array(
			'ID'          => (int) $input['id'],
			'post_status' => 'draft',
		),
		true
	);
	if ( is_wp_error( $result ) ) {
		return $result;
	}

	return aoedia_schedule_result( (int) $input['id'] );
}